Continuous rotary table



March 11, 1952 H. w. DENHARD CONTINUOUS ROTARY TABLE FILTER PROVIDED WITH MULTIPLE SCROLL DISCHARGER Fi led Nov. 10, 1947 4 Sheets-Sheet 1 INVENTOR. HHEEY W DENHHED March 11, 1952 H. w. DENHARD CONTINUOUS ROTARY TABLE FILTER PROVIDED WITH MULTIPLE SCROLL DISCHARGER 4 Sheets-Sheet 2 Filed NOV. 10, 1947 i INVENTORf. HHEEY VV-DENHFIED 1 K 55 66 L 2 BY 64 L a 54 8 Z March 11, 1952 H. w. DENHARD CONTINUOUS ROTARY TABLE FILTER PROVIDED WITH MULTIPLE SCROLL DISCHARGER 4 Sheets-Sheet 5 Filed Nov. 10, 1947 INVENTOR. HHEIZ'Y vv. DENHHED fifir fl/farwe/ March 11, 1952 DENHARD 2,588,912

H. W. CONTINUOUS ROTARY TABLE FILTER PROVIDED WITH MULTIPLE SCROLL DISCHARGER Filed Nov. 10, 1947 4 Sheets-Sheet 4 INVENTOR. HFIEEY w DENHHED 7% zdqa'm Patented Mar. 11, 1952 UNITED STATES PATENT OFFICE 2,588,912 ON NUO S R T Y .TAB F LT PROVIDED WITH MULTIPLE- SCROLL DISCHARGER 4 Claims. (01. 210-2025) This invention relates in general to a contin uous rotary table filter, and more particularly to a filter of this type provided with a multiple flight scroll discharger.

A rotary table filter includes a horizontally 55 disposed annular pan arranged for rotation about its own axis and defined by an annular bottom provided with upstanding inner and outer rims. Dividing this pan intoaplurality of identical and independent filtrate compartments are radially 1o extending division: strips secured along their lower edges to the pan bottom, and at their ends to the inner and outer upstanding pan rims. Disposed within each of the filtrate compartments so formed, is a drainage member or screen," and supported on each drainage screen is afilter medium fastened at its radial edges to the adjacent division strips, and atits peripheral edges to the inner faces of said inner and outer rims. Cardischarger of such construction that it occupies only a minimum of the filtering area of the filter.

The invention possesses other advantageous features, some of which, together with the foregoing, will be set forth at length in the following description, where the invention is; outlined in full with particular reference to the embodimerit illustrated in the accompanying drawings. Although such drawings illustrate a specific form of the invention, it is to be understood that it is not limited to such embodiment; since the invention as set forth in the claims may be embodied in other forms.

Referring. to the drawings:

Fig. l is a top plan view of a continuous table filter embodying the objects of this invention.

Fig. 2 is a section taken on the line 2- 2 of Fig. 1'.

Fig. 3 is a vertical section taken on the line ried by the pan is a coaxial automatic filter so 3 3 of Fig.1.

valve by which each of the filtrate compartments can be subjected successively to any desired differential pressure. In addition to this, some means must be provided for continuously remov- Fig. 4 is a vertical transverse section taken on: line 4-4 of- Fig. 3.

Fig. 5 is a vertical midsection of the automatic filter valve forming part of the filter shown in ing the solids deposited on the upper surface of Figs. 1 and 3'.

the filter medium as a result of the filtering cycle.

Although many expedients have been resorted to in attempting to eflicaciouslyaccomplish this latter purpose, none of them have proved to be an.

entirely satisfactory.

In general the, object of this invention is the provision in a table type continuous filter of a multiple flight discharge scroll disposed radially over the filter pan and of such construction that amount of the solids topass transversely through it to a point beyond the dischargezone.

More specifically, the object of this invention is the provision in a table type of filter of a mul tiple flight discharger scroll disposed radially over the filter pan and which the diameter of the scroll and the number and pitch of itsfiights are so correlated that they form an effective barrier or dam against the passage of solids transversely therethrough, and form spaced parallel walls between which the solids are packed and through which the solids slide during their bodily radial movement over the filter medium and over the outer rim or lip of the filter.

A further object of this invention is a provision Fig. 6 is a bottom plan view of the wear plate shown in Fig. 5'.

Fig. 7 is a top plan view of the valve body shown in Fig. 5.

The filter shown in these various figures com-- prises an annular pan generally designated by the reference numeral l, and which includes an annular plate 2 having a slight downward in-- clination towards the axis thereof, and a circular upwardly extending inner rim 3 welded or otherwise secured to the bottom plate l and a circular upwardly extending outer rim 4 likewise similarly secured to the bottom plate 2. Concentric with the outer rim 4 and outwardly spaced therefrom is an upstanding plate 5 and fastened across the upper edges of the plate- 5 and rim 4 is an annular plate 6 forming a lip over which the solids'deposited on the filter medium of the filter must be discharged as shown in Fig. 3. Welded to the lower face of the annular plate 2 adjacent its inner end is a downwardly extending ring 1, and welded to theplate 5 and ring 1 beneath the bottom 2 are a plurality of radially extending angle irons 8. Depending from the annular pan l and welded to the angle irons 8 are a pair of spaced concentric rings 9 and I I bridged by an upper ball race 12 and supported on a lower angle ball race l3. The lower race I3 is in turn welded to an annular in a continuous table filter of a multiple scroll plate M supported by an annular pedestal l5.

Covering the top of the rim 3 and welded thereto is a circular plate l6 and depending from this plate and welded thereto is a concentric valve pipe 1?. Welded to the plate It concentric therewith is a stepped stub shaft l8, and mounted over the upper end of this shaft is a flanged bushing l9. Fastened to the upper end of the shaft 18 by the cap screw 2! is a washer 22 serving to hold the bushing [9 in place. Surrounding the bushing I9 is a sleeve 23, and welded to the sleeve 23 and extending on either side thereof is an angle iron 2 (see Figs. 1, 2 and 3) serving as a cross arm. Welded to the angle iron 24 on either side of the shaft 58 is a ring 25 serving as a boss, and seated in each of these rings and in a concentric bore formed in the vertical leg of the angle iron 24 is a bearing ring 26. Seated in each of the rings 26 is a pin Zl provided with a head 28, and welded to'each of the heads 28 is an inner cross member 29 of a rectangular frame generally designated by the reference numeral 3!, and which extends radially of the filter and overlies the filter pan In addition to the inner cross member 2f; which is of channel form, the rectangular frame 3|! includes a pair of parallel side members and 33 of channel construction, and an outer angle iron cross member 36. The outer end of the rectangular frame 3| is mounted at its corners on a pair of upstanding legs 35 and 36 supported on suitable pedestals 3i.

Accommodated within the rectangular frame 3! is a rectangular scroll supporting frame generally designated by the reference numeral 3%, and which includes a pair of opposed angle iron cross members 39 and M and a pair of opposed parallel side members t2 and it. Each of the side members 62 and 33 is provided at either end thereof with a vertical slot 35, and each of the side members 32 and 33 of the frame H is provided at either end thereof with a horizontal slot 35. The scroll supporting frame 38 may be conveniently and adjustably mounted on the outer frame 3! by bolts d6 passing through the four pairs of crossed slots M and d5. Fastened to the lower faces of the cross members 39 and ll are aligned bearings ll and 48, and journaled in these bearings is a shaft 43 on which is mounted a scroll generally designated by the reference numeral i and which includes overlapping flights 52, 53 and 5d. The outer end of the scroll Si is provided with a circular guard 55 and fastened tothe outer end of the shaft 59 is a sprocket 56. 1

Extending across the side members 32 and 33 of the outer frame 3! is a channel 51, mounted on this channel is an electric motor 58 provided with a speed reducer 59 including a drive shaft til. Keyed to the drive shaft 81 is a sprocket t2, and extending around this sprocket and the sprocket 5c is a roller chain By this means the scroll 5! can be driven at any desired speed within the limits of the motor and its associated speed reducer.

The pan i is divided into a plurality of identical filtrate compartments M by radially extending division strips 65 welded along their lower edges to the annular plate 2, and at their ends to the inner and outer rims 3 and i. Welded to the upper edge of each of the division strips 65 is a strip 66, similar strips 6? and E53 being welded to the inner walls of the rims 3 and t so as to form a frame over each of the filtrate compartments. Seated on these frames within each of the filtrate compartments is a drainage screen 69 provided on'its lower surface with radial ribs 7!, the ends of which overlie the strips 61 and 58. Welded to and the upper face of each radial strip 66 is a channel l2, and welded to the upper face of each of the strips 61 and 53 is an angle iron 73 which with the rims 3 and d form a channel similar to the channels i2. Disposed over each of the drainage screens 69 is a filter medium 74, the peripheral edges of which are accommodated in the radial channels 12 and in the peripheral channels formed by the angle irons l3 and the inner and outer rims 3 and 4. Each section of the filter medium 74 is locked in place over its associated filtrate compartment by means of any suitable calking 75 such as manila rope, asbestos or lead, depending upon the use to which the filter is to be put.

As shown in Fig. 5, there is welded to the lower end of valve pipe ii a pipe plate it provided with a circular row of pipe receiving bores l1, there being one such bore for each of the filtrate compartments 64. Seated over the outer face of the pipe plate i6 is a wear plate 38 provided with a circular row of bores l9 arranged to register with the bores ll of the pipe plate 78. The wear plate '68 is fastened to the pipe plate 16 by machine screws 8!, the heads of which are receivable in countersinks 82. Extendin into each pair of registering bores Ti and i9 is a filtrate pipe 83 passing through an opening 3d formed in the valve pipe I? and communicating at its upper end as shown in Fig. 3 with one of the filtrate compartments 64. The filtrate pipes 83 are supported intermediate their ends from the valve pipe ll by lugs d5 fastened to the pipe IT by machine screws 86.

Seated over the lower face of the wear plate 18 is a valve body 8? held against rotation by being secured to any stationary portion of the filter foundation in accordance with well known practice. As shown in Figs. 5 and 7, the upper face of the valve body 87 is provided with an annular channel 88 concentric with the bores 71 and 79. The valve body 31 is provided with a central hub 89 and formed integral with this hub are a number of radially extending spiders 9i, 92, 93 and 94 serving to divide the annular channel 88 into arcuate ports $5, Q53, 9? and 93.

In accordance with well known practice, and as shown in Fig. 7, the annular channel 88 is arranged to receive arcuate strips or bridges such as NH and see for the purpose of blanking off any desired portion or portions of the arcuate ports 95, 96, Si and S3. Seated over the lower flanged face of the valve body tl'l is a cover plate )3, this plate being secured to the valve body' by machine screws such as tilt and W5. Formed in the cover plate IE3 is one or more bores H33 arranged to communicate in accordance with well known practice with any suitable source of Hit by means of which the valve may be con-v .nected to a suitable source of subatmospheric pressure. The valve body 8'! is: retained in its operative position by means of a bolt ml extending through the plate I83, the hub 89, the wear. plate '53, and the pipe plate '76. Disposed over the upper end of the bolt I 01 is a washer I08 and a nut we, the bolt being fixed against bearing is a washer II3.

rotation with respect to the pipe plate 75 and the wear plate 78 by a key I I I. Mounted on the bolt I 01 immediately beneath the cover plate I03 is a thrust bearing II 2, and beneath this thrust Engaging the lower face of the Washer II3 is a spring H4 the lower end of which abuts a washer II 5. Threaded over the lower end of the bolt I! is a double lock nut generally designated by the reference numeral II6. By means of this construction the valve body 81 can be biased against the lower face of the wear plate I8 to any extent desired.

Since the valve body 81 is held against rotation as above described, and since the filter and its associated valve pipe I'I, pipe plate 16 and wear plate 18 rotate with respect to the valve body, it will be seen that the lower end of each of the filtrate pipes 83 will successively communicate with the arcuate valve ports 95, 96, 91 and 98 so as to be successively subjected to whatever pressure these ports are maintained at. Normally, the pick up or cake formation cycle proceeds under the influence of a vacuum as likewise does the washing cycle, if washing is resorted to. desired to apply a reverse pressure to each of the filtrate compartments so as to loosen the cake II'I formed and carried thereon.

As shown in Figs. 1 and 3 there is fastened to the plate 9 of the upper ball race on which the annular pan I is supported, a spur gear Iii; ar-

ranged to mesh with a sprocket II9 (Fig. 1) driven by a speed reducer I21. The speed reducer I2I is in turn driven through a belt I22 by a set of spring biased cone pulleys I23 mounted on the shaft I24 of a motor I25. The motor I25 can be made to slide on its base I25 by means of a manually controlled screw I2! so as to increase or decrease the space between the two members of the pulley I23.

The scroll should consist of no less than three flights and the pitch thereof should be substantially equal to their diameter. The diameter of the flights depends upon the depth of the filtrate compartments 64, that is, the distance between the upper edge of the outer rim 4 and the filter medium I4. For many purposes this depth would be in the order of 5 or 6 inches, in which case the diameter of the scroll should be such as to permit ample clearance between the scroll shaft and the upper edge of the rim i so that the cake II! can be readily discharged between the outer rim and the scroll shaft. By resorting to these dimensions the three flights of the scroll will form a substantial dam or barrier across the entire width of the filter pan, thereby preventing the passage of the cake II'I through the scroll before the cake has been made to advance to and over the outer rim 4. In this connection it is to be observed that the function of the scroll is twofold. It must progressively move the cake outwardly towards the rim 4 and simultaneously lift the cake over this rim, and this must be done without permitting the cake to advance beyond the scroll. A continuous filter of any kind is only as effective as the means used for discharging it, for if any substantial amount of solids are permitted to remain on the filter medium, the filter medium will eventually become clogged to a point where further filtration becomes uneconomical. In addition then to the requirements above set forth, there should be At the discharge zone it may be a relatively close clearance between the scroll and the filter medium.

From the above description it will be noted that continuous table type of filter has been provided wherein discharge is effected by a multiple flight scroll having a sufficient number of flights of such a pitch that it forms an effective barrier or dam across the entire width of the pan and by means of which the cake formed and carried by the pan can be effectively moved outwardly thereon and over the rim thereof. Furthermore, the scroll is of such a nature that it occupies only a minimum area of the filter and can be readily adjusted with respect to the filter pan.

I claim:

1. A continuous rotary table filter comprising: an annular pan divided by division strips into a plurality of identical filtrate compartments; a filter medium covering each of said compartments, said pan being provided with inner and outer rims extending substantially above said filter medium; a central upstanding post supported by said pan; an outer horizontally disposed frame supported at its inner end from said post and its outer end by a pedestal; an inner frame adjustably mounted within said outer frame; aligned bearings carried by said inner frame; a scroll discharger journaled in said bearings and receivable within said pan between its outer and inner rims immediately above said filter medium, and a variable speed driving mechanism mounted on said outer rectangular frame for driving said scroll, said scroll having at least three flights each having a pitch equal to the outer diameter of said scroll.

2. A rotary table filter comprising: an annular pan divided by division strips into a plurality of identical filtrate compartments; a filter medium covering each of said compartments, said pan being provided with inner and outer rims extending substantially above said filter medium; a multiple flight scroll mounted radially over said table with its outer end immediately adjacent the inner surface of said outer rim and in position to discharge cake formed on said filter medium, over said rim.

3. A rotary filter of the character defined in claim 2 wherein said multiple flight scroll is provided with at least three flights.

4. A rotary table filter of the character defined in claim 2 wherein said multiple flight scroll is provided with at least three flights, each having a pitch substantially equal to the outer diameter of said scroll.

HARRY W. DENHARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 371,609 Marr Oct. 18, 1887 832,874 McFlory Oct. 9, 1906 1,001,660 Macklind Aug. 26, 1911 2,042,308 Hardy May 26, 1936 FOREIGN PATENTS Number Country Date 287,513 Germany Sept. 2'7, 1915 402,505 Germany Sept. 20, 1924 494,209 Germany Mar. 20, 1930 

